Screen share not installed

[Paul777]

I have just purchased a brand new 65" LG Smart TV, It was to replace my old 50" LG Plasma which was about 15 years old and not a smart TV. I turned on the TV for first time set up. The old TV picked up all the digital stations perfectly. but the new TV was missing most of the channels and the ones I did get were breaking up, unwatchable so I retuned the aerial. This time it got even fewer channels and the ones I got said " no signal " so, no picture, no sound. I tried the old TV with the same aeriel cable and all channels ran perfectly. Put the same cable into new TV, retuned it AGAIN and got the same result, no working channels. I had advertised the old TV for sale. It is now sold so I ended up having to go out and buy a set top box just to watch TV after paying £699 for a brand new TV. Seriously not impressed.

  Problem number two. The reason I bought the TV is to stream my collection of movies from my Windows 10 desktop PC. Turns out my new TV that wont let me watch TV channels doesn't have screen share installed. MY PC and TV are connnected to the same wireless network. When I click on " connect to a wireless display "  my LG TV shows up as connected in "other devices " but as Screen Share is not installed on my TV I cannot stream content.  If I had an Apple device I can use Air Play but I cannot abide Apple.  TV Cast LG works with Android but my movies and music are on my Windows 10 PC. I dont even have the option to download Screen Share from LG's online appstore, it isnt available.The only option I can think of is to buy a Chromecast which means after spending £699  and having to go out and buy a set top box, I'm gonna be out even more money. I wasreally impressed with my old LG TV. I just wanna take a sledgehammer to this one but cant because I have already spent too much money on it. 

PS I also spent half aday trying to register the warranty online which your system wouldnt permit me to do but after several hours on the phone I finally maaged to do so. That was Friday 8th of May but when I logged onto my account today it told me I have no productts registered. YESI HAVE. I EVEN TOOK OUT THE EXTENDED WARRANTY !!! I will never spend another penny on an LG product and I will never recommend LG to anyone so long as I live. 

CAN SOMEONE PLEASE TELL ME HOW TO CAST FROM A WINDOWS 10 PC BEFORE MY HEAD EXPLODES, thank you.